While cleft palate is one of the most common congenital malformations of the maxillo-facial region in man, the etiology of this defect remains poorly understood. To secure a better knowledge of normal morphogenetic events for the secondary palate, the application will study: (1) the role that the contractile protein actin has in palatal shelf development, and (2) the role of nerves in palatal shelf morphogenesis. Specifically, the aims of the study are: (a) to study through immunofluorescent techniques the sequential distribution of actin within epithelial and mesenchymal cells during that period of time in fetal development when palatal shelf elevation takes place; (b) to produce an antibody against actin that would give us a pure antibody with which to work in the above studies; (c) to study at the ultrastructural level the intracellular position of actin by the binding of heavy meromyosin; (d) to study in vitro the effects of smooth muscle contracting agents, plus the effects of complement, and the prostaglandins on epithelial and mesenchymal cells in excised palates; (e) to study whether agents that promote cellular contraction may be produced by the placenta and uterus; (f) to study the influence of nerves on palatal shelf development.